Current Seminar Series

Formal methods tend to get bad press because they are perceived as being
abstract, obscure, dry, and basically not very interesting except for the
mathematically inclined. This talk aims to show that they can be fun, by
using LOTOS on a variety of rather unconventional applications for a formal
method.

It will be seen how the classical n-body problem in mechanics can be
generalised and formalised in LOTOS. A number of variants are produced by
instantiation of the common specification framework. These include a
pendulum, Newton's cradle, Brownian motion, gas motion, the `game of life'
and an orrery. It will be shown how these are derived from the generic
framework using a configuration tool. The resulting LOTOS specifications are
simulated automatically to graphically animate the system behaviour. Live
demonstrations will be given of the approach.

It is shown how Dill (Digital Logic in Lotos) can be used to specify,
verify and test asynchronous (unclocked) hardware designs. New relations
for (strong) conformance are defined for assessing a circuit implementation
against its specification. An algorithm is also presented for generating
and applying implementation tests based on a specification. Tools have been
developed for automated verification of conformance and generation of
tests. The approach is illustrated with three case studies that explore
speed independence, delay insensitivity and testing of sample asynchronous
circuits.

The convergence of computing and telecommunications is well documented. One aspect is the concept of programming networks, that is programming networks to carry out value-added services. In a sense the existing telephony networks are programmable. Services such as 1471 and call waiting have been programmed into the network nodes. But it is a clumsy, costly, and certainly slow affair.

Attempts such as the Intelligent Network attempt to alleviate this, but this still shows a rate of service introduction many orders of magnitudes less than that of internet applications. The approach is steeped in the traditions of telephony.

In contrast concepts such as active networks, programmable networks, and mobile agents reflect the computing and IP world. Radically different approaches are advocated that promise a much more rapid introduction of services.
This seminar will describe these various approaches and will address the impact on the nature of future telecommunication services engineering.

3rd November 2000, 11.00-12.00, B4(note time and place have been changed, and differ from normal)

Over the next few years, the progressive advancements of Moore's Law start
to encounter increasingly challenging hurdles within the confines of
conventional semiconductor technology. These hurdles are both technological
and economic, and place silicon in the position of being vulnerable to a
`disruptive technology' upstart that could assume at least part of the
conventional semiconductor empire. The talk will consider the technology
factors, the economic context, and the changing demands of technology users.
With these in mind, the talk will look at the suite of alternative
technologies from which a next generation computing platform could select.
The speaker wonders whether neural technology would be ready in time for
this challenge, or if it might prefer to wait out this dance and try again
in about 10 years time!

15th November 2000, 13.00-14.00, 4B94(note different time and day from normal)

One of the main problems in industrial testing is the enormous number of
test cases that can be derived from any complex communication protocol. Due
to budget constraints and tight schedule, the number of test cases has to
be within a certain limit. However, having a limit raises the following
issues. What criteria should be used for selecting the test cases? How can
we ensure that important test cases have not been excluded? A good test
case is one that has a high probability of finding undiscovered errors. One
of the selection criteria is by means of determining the value of a test
case. By assigning a value to each of the test cases of a test suite, the
relative importance of each of the test cases can be ranked and an optimal
test suite can then be designed. The value of a test case should be
measured in economic terms, which could be based on the probability that a
particular case will occur and the consequence if it fails. In this
seminar, a method for assigning a value to each of the test cases of a
communication protocol test suite will be presented.

Quilting (including the patchwork which the typical quilter
indulges in) is primarily a leisure activity, one that seems to
have little to do with computing or mathematics. However, quilting
yields many varied combinatorial problems concerning patchwork (e.g.
aesthetic or practical layout arrangements) and social arrangements
(e.g. how to organise a group project to make everything run smoothly).
Two examples of such problems will be presented together with their
solutions, which were found using such tools as functional programming
and latin squares.

Networked Appliances are popularly viewed as one of the next major Internet
growth areas. An example appliance is an alarm clock that can adjust its
wake-up time based on your calendar, current weather and traffic
conditions. Another is an Internet-enabled home security system that allows
you to see the people approaching your home when you are in the office.
Another example, seen in a recent United States TV advertisement, is a
refrigerator that reports to a service station when it needs maintenance,
without ever needing to inform the owner. The application of Internet
technology to appliance devices opens up whole new vistas of exploitation,
the extent of which we can only guess at today.

Within this talk, we discuss the current state of the art in Networked
Appliances and examine some of the challenges that need to be addressed
before they are suitable for the mass market.

Computer speech recognition is an important subject that has been studied
for many years. Until relatively recently, classical mathematics and signal
processing techniques have played a major role in the development of speech
recognition systems. This includes the use of frequency-time analysis, the
Wigner transform, applications of wavelets, and a wide range of Artificial
Neural Network paradigms. Relatively little attention has been paid to the
applications of random scaling fractals for speech recognition. The fractal
characterisation of speech waveforms was first reported by Pickover and Al
Khorasani who investigated the self-affinity and fractal dimension for
human speech in general. They found a fractal dimension of 1.66 using Hurst
analysis. In this talk we investigate the use of fractal dimension
segmentation for feature extraction and recognition of isolated words. We
will discuss a few preliminaries which relate to Speech Recognition
techniques, Sampling and Data Extraction. This will include the magnitude
of the data and the number of zero crossings in the data. The talk will
then consider the use of fractal geometry for segmenting digital signals
and images. A method of texture segmentation is introduced which is based
on the Fractal Dimension. Using this approach, variations in texture across
a signal or image can be characterised in terms of variations in the
fractal dimension.
By analyzing the spatial fluctuations in fractal
dimension obtained using a conventional moving window approach, a digital
signal or image can be texture segmented. This is the principle of Fractal
Dimension Segmentation (FDS).